Crankcase Pressure
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Joined: Mar 2004
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Crankcase Pressure
My diesel engine has developed high air pressure in the crankcase. Although the engine is the small 4-cylinder Mitsubishi turbo used in the 87 Ranger perhaps those having the larger engines can help with solving my problem.
The engine soon after starting builds up enough pressure so engine oil is forced out any place it can get through. Removal of the dip stick results in an "Old Faithfull" of oil. The mechanic has given up with solutions other than piston blowby. Yet the engine runs fine and does not act as if a cylinder is not firing.
Removal of the valve cover breather hose indcates it is not pluged up and pressure flows through. Yet the pressure in the crankcase is high enough to force out quantities of oil.
I can not understand how there can be blowby and still have the cylinder fire.
Any suggestions??
The engine soon after starting builds up enough pressure so engine oil is forced out any place it can get through. Removal of the dip stick results in an "Old Faithfull" of oil. The mechanic has given up with solutions other than piston blowby. Yet the engine runs fine and does not act as if a cylinder is not firing.
Removal of the valve cover breather hose indcates it is not pluged up and pressure flows through. Yet the pressure in the crankcase is high enough to force out quantities of oil.
I can not understand how there can be blowby and still have the cylinder fire.
Any suggestions??
Posting Guru
Joined: Aug 2004
Posts: 2,417
Likes: 4
From: Braham MN
pull the whole breather assembly out of the valve cover so you can see into the valve cover. removing the hose will prove the hose isnt plugged but the actual breather might be plugged. check your oil for signs of raw fuel in it, a strong diesel smell in the oil, real thin oil. you might still have a bad cylinder with alot of piston blowby and still have it run, does the exhaust smoke alot too?? just a shot in the dark but maybe your oil is WAY over full and it is finding its own way out. But I would guess the last one isn't what is happening. 
Diesel rod
Diesel rod
